Extracellular Matrix 2

Basal Lamina

Introduction

This second lecture on ECM will cover the glycoprotein components of ECM and specialized epithelial ECM. Finally I will discuss some key experiments exploring the role and function of the ECM of epitheilia (basement membrane) and connective tissues. Basement membranes are mainly composed of laminins, collagen IVs and proteoglycans.

With the epithelial ECM the term "basement membrane" is used with light microscopy and "basal lamina" is used with electron microscopy.

The following peer assessment exercise should be completed before next lab (Lab 8 - 2 May) as your individual assessment for this week (lab missed due to public holiday).

Your answer should be pasted in 2 places

onto each project discussion page (Note you should add anonymously to the discussion page)

your own individual student page for my assessment.

Each individual will provide a brief assessment of the other groups projects. This should take the form of a brief critical (balanced) assessment identifying both the positive (good) and negative (bad) aspects of the project page as it currently exists online.

You may if you choose, use the final project assessment criteria as a guide. Though you are also welcome to use your own criteria.

Group Assessment Criteria

The key points relating to the topic that your group allocated are clearly described.

The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.

Content is correctly cited and referenced.

The wiki has an element of teaching at a peer level using the student's own innovative diagrams, tables or figures and/or using interesting examples or explanations.

Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.

Relates the topic and content of the Wiki entry to learning aims of cell biology.

Clearly reflects on editing/feedback from group peers and articulates how the Wiki could be improved (or not) based on peer comments/feedback. Demonstrates an ability to review own work when criticised in an open edited wiki format. Reflects on what was learned from the process of editing a peer's wiki.

Evaluates own performance and that of group peers to give a rounded summary of this wiki process in terms of group effort and achievement.

The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.

Develops and edits the wiki entries in accordance with the above guidelines.

Basement membranes (BMs) are specialized extracellular scaffolds that provide architecture and modulate cell behaviors in tissues, such as fat, muscle, endothelium, endometrium, and decidua. Properties of BMs are maintained in homeostasis for most adult tissues. However, BM ultrastructure, composition, and localization are rapidly altered in select uterine tissues that are reprogrammed during pregnancy to enable early maternal-embryo interactions. Here, our data exhibit both static and dynamic BMs that were tracked in mouse uterine tissues during pre-, peri-, and postimplantation periods of pregnancy. The data exhibit spatial-temporal patterns of BM property regulation that coincide with the progression of adapted physiology. Further interpretation and discussion of these data in this article are described in the associated research article titled, "Embryo implantation triggers dynamic spatiotemporal expression of the basement membrane toolkit during uterine reprogramming" (C.R. Jones-Paris, S. Paria, T. Berg, J. Saus, G. Bhave, B.C. Paria, B.G. Hudson, 2016) [1].

The current basement membrane (BM) model proposes a single-layered extracellular matrix (ECM) sheet that is predominantly composed of laminins, collagen IVs and proteoglycans. The present data show that BM proteins and their domains are asymmetrically organized providing human BMs with side-specific properties: A) isolated human BMs roll up in a side-specific pattern, with the epithelial side facing outward and the stromal side inward. The rolling is independent of the curvature of the tissue from which the BMs were isolated. B) The epithelial side of BMs is twice as stiff as the stromal side, and C) epithelial cells adhere to the epithelial side of BMs only. Side-selective cell adhesion was also confirmed for BMs from mice and from chick embryos. We propose that the bi-functional organization of BMs is an inherent property of BMs and helps build the basic tissue architecture of metazoans with alternating epithelial and connective tissue layers.

PMID 23844050

Archive

MH - note that content listed below will not match exactly current lecture structure but has been selected as having similar content

History

Below are some example historical research finding related to cell junctions from the JCB Archive.

1978Basal lamina instructs innervation Joshua Sanes and Jack McMahan show that regenerating nerve axons take their cues for new synapse formation from the extracellular matrix (ECM) of muscle cells and not from the muscle cells themselves.

ECM Scaffold - Tissue Engineering

“Decellularized tissues and organs have been successfully used in a variety of tissue engineering/regenerative medicine applications, …Each of these treatments affect the biochemical composition, tissue ultrastructure, and mechanical behavior of the remaining extracellular matrix (ECM) scaffold, which in turn, affect the host response to the material.”

Books

PubMed

PubMed is a service of the U.S. National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals for biomedical articles back to 1948. PubMed includes links to full text articles and other related resources. PubMed

PubMed Central (PMC) is a free digital archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health (NIH) in the National Library of Medicine (NLM) allowing all users free access to the material in PubMed Central. PMC

Online Mendelian Inheritance in Man (OMIM) is a comprehensive compendium of human genes and genetic phenotypes. The full-text, referenced overviews in OMIM contain information on all known mendelian disorders and over 12,000 genes. OMIM

Entrez is the integrated, text-based search and retrieval system used at NCBI for the major databases, including PubMed, Nucleotide and Protein Sequences, Protein Structures, Complete Genomes, Taxonomy, and others Entrez